The Augustinian Prior General (world leader) sent Louis to Portugal in 1525 with a mandate to reform Augustinian life there. He served as Director of Novices and Prior.

By personal example and wise leadership, Louis was instrumental in restoring strict religious observance, proper discipline and a spirit of prayer in the Order. So notable was this change that the Portuguese Jesuits decided to send their candidates to the Augustinian school so that they would be instructed in prayer and meditation.

Louis was nominated to be Bishop of Viseo. But no amount of persuasion could persuade Louis to accept episcopal ordination.

He wrote many spiritual books. His reputation as a humble and austere religious grew. A year before Louis died, Jerónimo Román wrote,

The religious priest Louis Montoya, ... throughout his long life has never grown tired of doing penance and living the austere life as he has always done.

He died in 1569. In the register of deaths appears the notation that Louis "governed the Province of Portugal in a most holy way."